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From: news@linus.mitre.org (News Service)
Newsgroups: sci.bio
Subject: Re: Primary colors in human color vision
Message-ID: <1991Mar25.143710.28872@linus.mitre.org>
Date: 25 Mar 91 14:37:10 GMT
References: <00945FE5.1F9B5480@aclcb.purdue.edu>
Organization: MITRE Washington CCEL Prototyping
Lines: 29
Nntp-Posting-Host: ccels3.mitre.org

Your question about how a tv works is a little too open ended for me to be sure
what you are asking, but it is true that a color tv uses only red, green, and
blue.  There are three "electron guns" that strike unique targets on a phosphor
film at the front of the crt.  (If a gun strikes the wrong target, it will
produce the color of the target, so it is actually the film on the crt that
produces the light.  
From: bkillam@ccels3 (bill killam)
Path: ccels3!bkillam

The human eye has cones for the same three primary additive colors (red, green,
and blue).  This is based on some work in microspectrophotometry where single
cones in the eye were targeted by different wavelenghts of light and the 
resultant reflcetion is measured (the differences in input/output determines
what input was absorbed.)  An alternative hypothesis has been developed (as I
recall, primarily to explain the after image effect - "seeing" complimentary
colors when the stimulas is removed.)  This hypothesis is called the opponent
process theory.  This theory is based on observation (as far as I know).  The
two theories have always been in conflict since neither can explain the findings
of the other.

Bill Killam

 


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    | Bill Killam           | bkillam                               |
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